Question 1183301
The maximum is where x=-b/2a=-1250/-70=$17.86  and will make $4660.71 in profit. That is the price at which profit is maximized. 
The roots represent where the profit is 0 or breakeven.
Set y=3000 and solve for -35x^2+1250x-9500=0
or 35x^2-1250x+9500=0; 7x^2-250x+1900=0
x=(1/14)* (250+/- sqrt (9300))
=(1/14)(250+/- 96.44)
=$24.74 or $10.98 
between ($10.98 and $24.74)

{{{graph(300,300,-10,30,-250,6000,3000,-35x^2+1250x-6500)}}}